1. Field of Invention
The present invention relates to an improved method for the manufacture and fitting of partial denture dental appliances, such as a partial denture, which when secured to the crowned abutment teeth does not create any damaging stress forces to the abutment teeth.
2. Description of the Prior Art
Partial denture dental appliances in the form of partial dentures in order to replace and compensate for lost or damaged teeth are common. In practice, most partial dentures are secured to an abutment tooth for which in most cases is a natural tooth to which a crown or coping has been affixed. The partial denture is secured to this crown or coping by retentive means.
The practice in the past has been to take an impression of the patient's mouth and to cast a partial framework which would be secured to the crown on the abutment tooth in order to maintain the partial denture in position. The difficulty which arises in this method is that slight casting errors can create stresses and strains between the crowned abutment tooth and the saddles of the partial plate. These stresses and strains can serve to cause a loose fit of the partial denture and might quite possibly cause sufficient stress and strain on the abutment tooth that it too would have to be replaced.
Applicant's prior patents, U.S. Pat. Nos. 4,931,016 and 5,057,017 were directed to dental implant systems for securing a denture directly to the alveolar bone.
Applicant has developed a method for the manufacture and fitting of the partial denture dental appliance utilizing electrical discharge machining (EDM) methods which utilize low voltage and low amperage under reversing polarity to fabricate a partial dental appliance which eliminates the possibility of any stress and strain being exerted upon the crowned abutment tooth and results in a more secure and accurate fit.